Field of the Invention
Embodiments of the present invention relate to a display device, in particular, to a pixel structure, a display device having the pixel structure, and a manufacturing method of the pixel structure.
Description of the Related Art
Currently, an organic light emitting diode (OLED) unit and an active matrix organic light emitting diode (AMOLED) unit are widely used in a display device as an organic film electroluminescent device, due to their characteristics such as an excellent shock resistance, a wide visual angle, a broad range of operation temperature, a high contrast, an ability of flexible display, etc. In general, a pixel structure comprises a pixel defining layer (PDL) for defining a pixel aperture and an OLED unit disposed in the pixel aperture. The OLED unit comprises a first electrode layer, a second electrode layer and an organic luminescent layer packaged therebetween. A voltage is applied between the first electrode layer and the second electrode layer to excite the organic luminescent layer to emit light, the emitted light then exits from the pixel aperture.
In the OLED unit, the light emitted from the organic luminescent layer under a certain range of incident angles undergoes a total reflection on a surface of the organic luminescent layer and is then transmitted inside the organic luminescent layer, thereby an optical waveguide mode is produced inside the organic luminescent layer. At an interface between an edge of the organic luminescent layer and the pixel defining layer, light beams in a certain range of incident angles are possible to deviate from the light waveguide mode inside the organic luminescent layer and enter the pixel defining layer because the refractive index of the organic luminescent layer is close to that of the pixel defining layer. These light beams are substantially laterally transmitted, that is, they are transmitted in a direction which is substantially perpendicular to an emitted-light direction required for an effective display of the pixel structure. These light beams which are substantially laterally transmitted will be finally dissipated in the pixel defining layer if they are not controlled.